During or following manufacture it is customary for several articles as defined above to be laid horizontally, to await removal to the next manufacturing stage, to be taken to store, or to be made ready for delivery to a customer.
If the articles are stacked horizontally one above another, particularly if held in long-term storage, and are shaped so that they engage only at an edge they may sag or warp, and it is therefore desirable that the articles be stacked closely so that the degree of sagging of an article can perhaps be limited by the article below. Furthermore, if stack height is critical, then if articles are more closely stacked extra articles can be stored or be transported "as a stack".
The peripheral edges of articles are at risk from damage both during storage and transportation, and it is customary for the manufacturer, and often also the customer, to require article edge protection of an adequate thickness designed to reduce the likelihood, and/or severity, of any such damage.
It will be understood that although a desired edge protector shape may readily nowadays be formed in a plastic material, users are increasingly conscious of the environmental implications and the public reaction to the plastics disposal problem, particularly for "one trip" packaging materials. Many currently available edge protectors are manufactured from moulded polystyrene or polyethylene, but users have for some years been actively seeking environmentally acceptable alternatives; specifically, in a technical area in which recycled or recyclable materials may easily be employed, many manufacturers and users are increasingly resisting the use of materials which are not and/or may not be recycled, and instead would prefer to use recycled materials if of the same or similar cost and performance.
A known recyclable material is corrugated paper, and a convenient form of this is single-faced corrugated paper in which one corrugated sheet is adhered at corrugation peaks to a sheet of substantially planar paper.